Tata Steel contributes daily to the green transition that our country is currently undergoing, in multiple ways. This includes supplying steel produces with more scrap and less CO2 emissions, improving energy efficiency in all steel production processes, providing stronger steel to enhance vehicle safety and reduce fuel consumption, delivering smart steel to minimize total losses, producing tinplate to extend the shelf life of canned food and reduce food waste, supplying high-tech steel for longer-lasting and leak-resistant batteries.

Less steel, same strength, more competitive

Wind parks have not yet been mentioned in this sum-up. Why not? Because supporting structures for wind turbines are made of very thick steel plates, and machined ring flanges which are often made of more than 100 mm thick steel. Tata Steel Nederland specializes in high-quality thinner steel, in the form of coiled steel. Flat-rolled steel, which is used in our cars, washing machines, and food cans. Wind towers are made from plate thickness ranging from 40 to 100 mm, which are welded into rings, then rings welded into tower segments and then connected in-situ by ring flanges into a tower.

However, this may change soon, as a team of researchers from Tata Steel Nederland, in collaboration with, amongst others TU Delft, explores constructing wind towers with thinner steel plates that are just as strong and more competitive, representing a new advancement in wind tower construction. Hans van der Weijde, R&D Director Tata Steel: “This involves researching new and alternative forms of steel structures and connections, such as wind turbine assembly with (stiffened) panels or with spiral-like steel structures or with double-walled surfaces. Various industry stakeholders are involved in this research, as any technical innovations must also be practical and feasible.” This industrial consortium is led by Tata Steel Netherlands and TU Delft. Dr. Milan Veljkovic, Professor Steel and Composite Structures states: ”The wind turbines’ double-skin shell is a hybrid structure requiring innovation in connecting tower segments. Our main motivation is to improve the sustainability and competitiveness of such towers.” 

Innovation for an extended lifespan

In addition to reducing steel usage, another focus of this research is to extend the lifespan of wind towers. This goal aligns with the redeveloping of wind turbines to last longer. Wind towers also have to meet these targets in the nearby future. The current generation of wind turbines typically has a lifespan of 20 to 25 years. With these new development goals, a lifespan of more than 30 years is being aimed for. Furthermore, this new generation of even more sustainable wind turbines should be suitable for both onshore and offshore applications. With the planned green steel investments in IJmuiden, Tata Steel aims to make a significant contribution to the production of green energy using wind turbines manufactured from green steel.

The researchers from Tata Steel Nederland and the ‘Institute of Physics’ at the University of Amsterdam demonstrated the superior shock absorption of their metamaterial designs through numerous crash tests. For this purpose, the three-story industrial drop tower at Tata Steel was used. Dr. ir. Bernard Ennis, a researcher at Tata Steel Nederland, stated, "We can now confidently state that the newly developed metamaterials act as unique shock absorbers. The next step is to use an AI model to distribute the load more evenly. This way we can, for example, manufacture the casing of car batteries in such a way that the battery remains undamaged in a collision because the forces are diverted away from the battery. But this is just the beginning. With the use of these newly developed metamaterials, many life-saving applications are possible, such as using them for guardrails or making buildings earthquake-resistant."

What are metamaterials?

Metamaterials are materials whose structure has been altered, giving them different material properties than they naturally have. A straightforward example is steel. Steel is typically rigid or flexible. By changing the structure of steel, it acquires different steel properties, and its flexibility can be influenced as desired. The steel becomes, so to speak, 'smart, intelligent.' The researchers from Tata Steel Nederland and the University of Amsterdam have developed a new metamaterial together that can efficiently and repeatedly absorb shocks. Furthermore, this metamaterial can absorb more force with a smaller volume, making it lighter and therefore more sustainable.

New startup: 'Metamaterial Works'

The research will continue in the startup 'Metamaterial Works', focusing on further developing the new patented technique. Bernard Ennis will become the CEO of this startup, which aims to further develop the acquired knowledge for many more high-tech applications. Co-researcher and co-founder Wenfeng Liu stated, "Future applications range from cars and aerospace vehicles on the meter scale to microscopes and nanolithography on the micrometer scale."

Publication in Nature

The research results have been published in the prestigious scientific journal 'Nature'. Wenfeng Liu, Shahram Janbaz, David Dykstra, Bernard Ennis, and Corentin Coulais, "Harnessing plasticity in sequential metamaterials for ideal shock absorption," Nature 634, 842–847 (2024). https://doi.org/10.1038/s41586-024-08037-0

As we speak, steel is being researched in the ISS. This concerns steel that can be used for electric motors. The quality of this steel largely determines the efficiency of motors in, for example, electric cars. This directly contributes to the energy transition. These types of steel have a complex structure that partly arises during casting. The knowledge gained from this experiment is used in the casting process to prevent errors and to achieve better steel for this application. 

ESA and Tata Steel Nederland Collaboration

It is very imaginative; steel melted in space and then cooled and solidified again in a 'high tech' monitored process. In this co-production, Tata Steel Nederland provides specifically prepared steel samples and knowledge. ESA is responsible for the execution of the scientific experiment. The knowledge resulting from the various studies is available to everyone. Materials expert Wim Sillekens is involved in the space steel project from ESTEC/ESA and states: "For science, all the materials research within the 'Space for Science' program has already resulted in more than 1,600 publications, including a number of scientific articles together with Tata Steel."

Why steel research in space?

We ask this question to the Argentinian-Dutch scientist Dr. Begona Santillana. She works in the 'Research & Development' department of Tata Steel and researches the solidification of steel. Dr. Santillana is the initiator and manager of this steel research in space and explains its added value: "All the steel that surrounds you has once been liquid. And it is precisely in that process from liquid to solidified steel that much can go wrong. The solidification of liquid steel at very high temperatures, around 1500 degrees Celsius, is influenced by mechanical, thermodynamic, and thermo-physical properties. In the lab, we investigate all these properties, but the steel samples used for this purpose are also subject to gravity. In space, we don't have that problem, which leads to purer data.

How does it work?

Steel pellets of less than 10 grams, prepared by TSN, are placed on Earth in a batch with other samples in a kind of carousel and transported to the ISS by rocket. There, the carousel is placed in the double-walled 'Electro-Magnetic Levitator' (EML). In the EML, the steel pellets are then melted and solidified in a number of cycles. This happens while the astronauts are sleeping to prevent measurement errors due to movement. The process is monitored, and the data go 'real-time' to the 'Microgravity User Support Center', a support center of the ISS in Cologne, for data collection, among other things. Upon return to Earth, the steel samples go to Tata Steel Nederland and the University of Warwick in the United Kingdom for further research.

Energy saving and sustainability through steel research in space

For applications of steel, preventing errors in the process is crucial, and precise knowledge of solidification temperature and other thermo-physical properties is important. Dr. Santillana: "Through the knowledge obtained from this scientific research, we can realize the production of steel more efficiently. Moreover, thanks to the knowledge gained, we can produce different types of steel with fewer process problems. Indirectly, this leads to energy savings and a better product." Wim Sillekens (ESA) adds: "In our collaboration with Tata Steel Nederland, we have acquired a lot of knowledge about steel properties with an accuracy that cannot be measured in any other way. Many of the materials investigated in the EML are related to sustainability; in addition to steel, these are, for example, hard-magnetic materials and semiconductor materials, for applications in wind turbines and solar panels. These materials are critical for the green transition, and even small improvements in performance are of very great value on a global scale."

*Photo: ESA